2007 engine into 2002 with ecu swap.

raven007

Original poster
Member
May 10, 2019
7
GA
I am hesitant to post this as i know its been flogged before. I have searched and read etc etc. Lots of great info, this is more of a sanity check.

I have a 2002 TB with the original 4.2 thats right at 190k. It has a fair amount of mid/upper engine noise and I can tell power is dropping off. Things are not great.

I scored a dressed 2007 4.2 with lower mileage. I got everything. Complete harness, p12 pcm, manifolds, fuel rail. Even got the bit of harness that goes into the blue connector and goes through the firewall.

My skill level: I am comfortable with everything. The pulled out engine will most likely be repaired and put in a 49 chevy car with a colorado manual trans.

I am comfortable either splicing or repinning the blue connector. Everything else just goes together right?. I am aware my p10 ecu will work with this engine but I want the P12 because its more tuner friendly and I have everything so why not.

My questions are will HPtuners throw a mismatch vin/os error if I put my current vin into the P12, can turn off the SAIS codes and run my blockoff plate, and can I do the fan stuff to put the LS1 fans on? Am I missing anything huge here? Its all class 2.

I should mention I am not partial to efilive or hptuners, whichever will do the job the best here. I am also open to sending the PCM off to have what I need done, done.
 
Last edited:

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
I think it may be more the BCM that will throw a fit as it was not designed or programmed to work with the p12. There is also the issue with the fuel rail (return vs. returnless) that your 02 setup will not work work with the 07 returnless system.

It.might work.
 

Sparky

Member
Dec 4, 2011
12,927
Adamptong a return to returnless fuel system isn't so bad as you basically abandon the old return line. Going the other way is hard.
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Not really as you also have to replace the fuel pump since the fuel pressure regulator is in there as opposed to the fuel rail at the engine on the return system.
 

limequat

Member
Dec 8, 2011
520
You're asking for a crap ton of trouble. Please consider using the 2007 engine + 2002 electronics in your Traiblazer. This is 99% bolt in, and all your electronics will work. Then for your swap, you can use the 2007 Harness + 2002 engine.
This won't even require a reflash for the Traiblazer, do it in a weekend. For your project car, you would need a stand alone tune anyway - which Lime-Swap will gladly perform for $99 :smile:
 

raven007

Original poster
Member
May 10, 2019
7
GA
Yeah, that's probably what I will end up doing and put the P12 stuff on the shelf for a future project (the 49).

Can I send you a spare P10 and you fix the vin and do the tune?
 

TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,047
Brighton, CO
With an 07 engine, and a 02 computer, how are you going to get around the 58x and 12x expected? Or was that in 08 that it switched?
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
If you get a PCM from a same geared truck, you won't have any problems. Just check the code on the glove box sticker. VIN doesn't matter as you will need a security relearn regardless. And that PCM would need a CASE relearn. My advice would be to send in your PCM and use the spare while it's out for tuning. Then you won't need a CASE relearn as that is retained with your PCM when it comes back and be totally plug and play. The spare PCM will give you a code for it but won't affect anything.
 

raven007

Original poster
Member
May 10, 2019
7
GA
Yep 2008 is when the reluctor changed. I specifically sought out a low mile 2007 to give me the latest/newest engine that was compatible with my current pcm in case the p10 to p12 swap did not work out.
 

raven007

Original poster
Member
May 10, 2019
7
GA
Believe it or not this thing is still running. I crashed Monday and ended up buying another 2007 that was going to the scrapyard to repair the 2002. 2007 runs amazing but was an impound with no possibility of ever being titled/registered.
 
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